package compute;

import java.util.ArrayList;

import util.MyBitSet;
import data.DataBloc;
import data.Key;

public class DES implements BlocEncrypter {

	private Key key;

	/**
	 * Initial permutation
	 */
	private static final int[] IP = { 58, 50, 42, 34, 26, 18, 10, 2, 60, 52,
			44, 36, 28, 20, 12, 4, 62, 54, 46, 38, 30, 22, 14, 6, 64, 56, 48,
			40, 32, 24, 16, 8, 57, 49, 41, 33, 25, 17, 9, 1, 59, 51, 43, 35,
			27, 19, 11, 3, 61, 53, 45, 37, 29, 21, 13, 5, 63, 55, 47, 39, 31,
			23, 15, 7 };

	/**
	 * inverse de Initial permutation
	 */
	private static final int[] IPINV = { 40, 8, 48, 16, 56, 24, 64, 32, 39, 7,
			47, 15, 55, 23, 63, 31, 38, 6, 46, 14, 54, 22, 62, 30, 37, 5, 45,
			13, 53, 21, 61, 29, 36, 4, 44, 12, 52, 20, 60, 28, 35, 3, 43, 11,
			51, 19, 59, 27, 34, 2, 42, 10, 50, 18, 58, 26, 33, 1, 41, 9, 49,
			17, 57, 25, };

	/**
	 * permutation E
	 */
	private static final int[] E = { 32, 1, 2, 3, 4, 5, 4, 5, 6, 7, 8, 9, 8, 9,
			10, 11, 12, 13, 12, 13, 14, 15, 16, 17, 16, 17, 18, 19, 20, 21, 20,
			21, 22, 23, 24, 25, 24, 25, 26, 27, 28, 29, 28, 29, 30, 31, 32, 1, };

	/**
	 * permutation P
	 */
	private static int[] P = { 16, 7, 20, 21, 29, 12, 28, 17, 1, 15, 23, 26, 5,
			18, 31, 10, 2, 8, 24, 14, 32, 27, 3, 9, 19, 13, 30, 6, 22, 11, 4,
			25 };

	/**
	 * Matrice des permutation de S
	 */
	private int[][][] S = {
			{
					{ 14, 4, 13, 1, 2, 15, 11, 8, 3, 10, 6, 12, 5, 9, 0, 7 },
					{ 1, 0, 15, 7, 4, 14, 2, 13, 1, 10, 6, 12, 11, 9, 5, 3, 8 },
					{ 2, 4, 1, 14, 8, 13, 6, 2, 11, 15, 12, 9, 7, 3, 10, 5, 0 },
					{ 3, 15, 12, 8, 2, 4, 9, 1, 7, 5, 11, 3, 14, 10, 0, 6, 13 }

			},
			{ { 15, 1, 8, 14, 6, 11, 3, 4, 9, 7, 2, 13, 12, 0, 5, 10 },
					{ 3, 13, 4, 7, 15, 2, 8, 14, 12, 0, 1, 10, 6, 9, 11, 5 },
					{ 0, 14, 7, 11, 10, 4, 13, 1, 5, 8, 12, 6, 9, 3, 2, 15 },
					{ 13, 8, 10, 1, 3, 15, 4, 2, 11, 6, 7, 12, 0, 5, 14, 9 } },
			{ { 10, 0, 9, 14, 6, 3, 15, 5, 1, 13, 12, 7, 11, 4, 2, 8 },
					{ 13, 7, 0, 9, 3, 4, 6, 10, 2, 8, 5, 14, 12, 11, 15, 1 },
					{ 13, 6, 4, 9, 8, 15, 3, 0, 11, 1, 2, 12, 5, 10, 14, 7 },
					{ 1, 10, 13, 0, 6, 9, 8, 7, 4, 15, 14, 3, 11, 5, 2, 12 } },
			{ { 7, 13, 14, 3, 0, 6, 9, 10, 1, 2, 8, 5, 11, 12, 4, 15 },
					{ 13, 8, 11, 5, 6, 15, 0, 3, 4, 7, 2, 12, 1, 10, 14, 9 },
					{ 10, 6, 9, 0, 12, 11, 7, 13, 15, 1, 3, 14, 5, 2, 8, 4 },
					{ 3, 15, 0, 6, 10, 1, 13, 8, 9, 4, 5, 11, 12, 7, 2, 14 } },
			{ { 2, 12, 4, 1, 7, 10, 11, 6, 8, 5, 3, 15, 13, 0, 14, 9 },
					{ 14, 11, 2, 12, 4, 7, 13, 1, 5, 0, 15, 10, 3, 9, 8, 6 },
					{ 4, 2, 1, 11, 10, 13, 7, 8, 15, 9, 12, 5, 6, 3, 0, 14 },
					{ 11, 8, 12, 7, 1, 14, 2, 13, 6, 15, 0, 9, 10, 4, 5, 3 } },
			{ { 12, 1, 10, 15, 9, 2, 6, 8, 0, 13, 3, 4, 14, 7, 5, 11 },
					{ 10, 15, 4, 2, 7, 12, 9, 5, 6, 1, 13, 14, 0, 11, 3, 8 },
					{ 9, 14, 15, 5, 2, 8, 12, 3, 7, 0, 4, 10, 1, 13, 11, 6 },
					{ 4, 3, 2, 12, 9, 5, 15, 10, 11, 14, 1, 7, 6, 0, 8, 13 } },
			{ { 4, 11, 2, 14, 15, 0, 8, 13, 3, 12, 9, 7, 5, 10, 6, 1 },
					{ 13, 0, 11, 7, 4, 9, 1, 10, 14, 3, 5, 12, 2, 15, 8, 6 },
					{ 1, 4, 11, 13, 12, 3, 7, 14, 10, 15, 6, 8, 0, 5, 9, 2 },
					{ 6, 11, 13, 8, 1, 4, 10, 7, 9, 5, 0, 15, 14, 2, 3, 12 } },
			{ { 13, 2, 8, 4, 6, 15, 11, 1, 10, 9, 3, 14, 5, 0, 12, 7 },
					{ 1, 15, 13, 8, 10, 3, 7, 4, 12, 5, 6, 11, 0, 14, 9, 2 },
					{ 7, 11, 4, 1, 9, 12, 14, 2, 0, 6, 10, 13, 15, 3, 5, 8 },
					{ 2, 1, 14, 7, 4, 10, 8, 13, 15, 12, 9, 0, 3, 5, 6, 11 } }

	};

	/**
	 * constructeur avec initialisation de la clef à key
	 * 
	 * @param key
	 */
	public DES(Key key) {
		this.key = key;
	}

	/**
	 * constructeur avec initialisation de la clef aléatoire.
	 */
	public DES() {
		key = new Key();
	}

	/**
	 * permet de générer un nouvelle clef aléatoire.
	 */
	public void generateNewKey() {
		key = new Key();
	}

	/**
	 * @return la clef actuelle de DES
	 */
	public Key getKey() {
		return key;
	}

	/**
	 * écrase l'ancienne clef avec la nouvelle clef key
	 * 
	 * @param key
	 */
	public void setKey(Key key) {
		this.key = key;
	}

	/**
	 * chiffre un plaintext avec la clef du DES
	 * 
	 * @param plainText
	 * @return le texte chiffré.
	 */
	public DataBloc encrypt(DataBloc plainText) {

		MyBitSet bsTmp = plainText.getValue().clone();
		bsTmp = bsTmp.permute(IP);
		MyBitSet[] tmp = bsTmp.split();

		MyBitSet L = tmp[0];
		MyBitSet R = tmp[1];

		for (int i = 0; i < 16; i++) {
			MyBitSet buf = L;
			L = R;
			R = buf;
			R.xor(f(L, key.getKeyFromOriginalKey(i)));
		}
		return new DataBloc(R.concat(L).permute(IPINV));
	}

	/**
	 * déchiffre le bloc de 64 bits
	 */
	public DataBloc decrypt(DataBloc cipherText) {
		MyBitSet bsTmp = cipherText.getValue().clone();
		bsTmp = bsTmp.permute(IP);
		MyBitSet[] tmp = bsTmp.split();

		MyBitSet L = tmp[0];
		MyBitSet R = tmp[1];

		for (int i = 0; i < 16; i++) {
			MyBitSet buf = L;
			L = R;
			R = buf;
			R.xor(f(L, key.getKeyFromOriginalKey(15 - i)));
		}
		return new DataBloc(R.concat(L).permute(IPINV));
	}

	/**
	 * la fonction f utilisée dans l'algorithme de DES
	 * 
	 * @param Rn
	 * @param kn
	 * @return
	 */
	public MyBitSet f(MyBitSet Rn, MyBitSet kn) {
		MyBitSet result = Rn.permute(E);
		kn.xor(result);
		result = new MyBitSet(32);
		for (int i = 0; i < 8; i++) {
			int rowIndex = 0;
			if (kn.get(0 + i * 6)) {
				rowIndex += 2;
			}
			if (kn.get(5 + i * 6)) {
				rowIndex += 1;
			}

			int columnIndex = 0;
			for (int j = 0; j < 4; j++) {
				if (kn.get(j + 1 + i * 6)) {
					columnIndex += Math.pow(2, 3 - j);
				}
			}

			int val = S[i][rowIndex][columnIndex];
			if (val / 8 != 0) {
				result.set(0 + i * 6, true);
				val -= 8;
			} else
				result.set(0 + i * 6, false);

			if (val / 4 != 0) {
				result.set(1 + i * 6, true);
				val -= 4;
			} else
				result.set(1 + i * 6, false);

			if (val / 2 != 0) {
				result.set(2 + i * 6, true);
				val -= 2;
			} else
				result.set(2 + i * 6, false);

			if (val / 1 != 0) {
				result.set(0 + i * 6, true);
				val -= 1;
			} else
				result.set(0 + i * 6, false);
		}
		return result.permute(P);

	}

	public static void main(String[] args) {
		MyBitSet donnee = new MyBitSet("0100 0101" + "0101 0101" + "0101 0101"
				+ "0101 0101" + "0101 0101" + "0101 0101" + "0101 0101"
				+ "0101 0101");
		DataBloc d = new DataBloc(donnee);
		DES des = new DES();
		DataBloc r = des.encrypt(d);
		System.out.println(r.getValue().print());

		r = des.decrypt(r);
		System.out.println(r.getValue().print());
		r.getValue().flip(0, 64);
		System.out.println(!d.getValue().intersects(r.getValue()));

		String coucou = "âëélèbo?";
		@SuppressWarnings("unused")
		byte[] bytes = coucou.getBytes();
		ArrayList<DataBloc> a = DataBloc.toDataBloc(coucou);
		String resultCoucou = DataBloc.toString(a);

		System.out.println(resultCoucou);
		System.out.println((coucou.equals(resultCoucou)));

	}

}
